Derivatized Polyhydroxystyrenes with a novolak type structure and processes for preparing
the same

ABSTRACT

A process for preparing derivatized poly(4-hydroxystryrene) having a novolak type structure which comprises the steps of (i) supplying a solution of methanol containing 4-hydroxyphenylmethylcarbinol, (ii) subjecting said solution to an acid catalyzed displacement reaction for a sufficient period of time and under suitable conditions of temperature and pressure to convert substantially all of said carbinol to 4-hydroxyphenylmethylcarbinol methyl ether in solution, (iii) polymerizing said ether containing solution in the presence of a suitable acid catalyst for a sufficient period of time and under suitable conditions of temperature and pressure to form a novolak type polymer. New compositions of matter which comprise the derivatized poly(4-hydroxystyrene) prepared in the above manner and which have application in the electronic chemicals market such as in a photoresist composition, and in other areas such as in varnishes, printing inks, epoxy resins, copying paper, tackifiers for rubber, crude oil separators, and the like.

RELATED PATENT APPLICATIONS

This patent application is a division of pending patent application Ser.No. 12/080,872 filed Apr. 7, 2008, and which is a division of Ser. No.11/112,605 filed on Apr. 22, 2005 and which is now U.S. Pat. No.7,371,800.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a new derivatizedpoly(4-hydroxystyrene) (DPHS) and a process for the production of DPHSindirectly from 4-hydroxymethyl-carbinol (HPMC) and which DPHS has anovolak type structure which has utility in the electronic chemicalsmarket such as photoresist compositions. In addition to the use of DPHSin the microelectronic chemicals market, such DPHS can be employed instandard novolak applications such as varnishes, aniline printing inks,raw materials (e.g. curing agents) for epoxy resins, copying paper,tackifiers for rubber, crude oil separators, solder masks andphotoimageable coverlays for rigid and flexible printed circuit boards,and further, derivatized epoxy resins and polyisocyanuates which havebeen reacted with the hydroxy groups of the DPHS, such as paintformulations containing the same. The DPHS may also be used as aviscosity modifier for highly viscous polymers with the capability ofcrosslinking after casting and thus providing antioxidation protectiontherefore.

2. Description of the Prior Art

In the past, one of the ways of preparing poly(4-hydroxystyrene) (PHS)was the use of 4-hydroxystyrene (HSM) as the starting material; noteEuropean Patent Application No. 0-108-624. 4-Hydroxystyrene is awell-known compound in the art.

Although there are several known ways to prepare 4-hydroxystyrene, theseknown methods are not commercially feasible in the further utilizationof the 4-hydroxystyrene. The 4-hydroxystyrene itself is difficult toisolate since it (1) readily decomposes, and (2) is toxic via skinabsorption and, as a result, those skilled in the art have made numerousattempts at finding a method of synthesizing PHS in a manner whichavoids using the 4-hydroxystyrene as the starting material.

The following prior art references are disclosed for informationalpurposes.

U.S. Pat. No. 5,087,772 (issued Feb. 11, 1992) discloses the preparationof HSM by reacting 4-acetoxystyrene (ASM) with a suitable alcohol in thepresence of a catalytic amount of a suitable base.

U.S. Pat. No. 5,340,687 discloses the alkylation of a linearpoly(4-hydroxystyrene).

European Patent Application No. 0-128-984 (publication no.) filed Aug.30, 1983 discloses a process for the production of para-vinyl phenol(HSM) by dehydrogenation of para-ethyl phenol.

European Patent Application No. 0-108-624 (publication no.) filed Nov.4, 1983, discloses a process for the production of p-vinyl phenolpolymer (poly(4-hydroxystyrene) polymer—PHS) by polymerizing p-vinyl(HSM) in the presence of water and iron.

U.S. Pat. No. 4,032,513 (issued Jun. 28, 1977) discloses a process ofproducing PHS by cationically polymerizing HSM in the presence of anitrile such as CH₃CN using a cationic polymerization initiator in ahomogeneous reaction system.

U.S. Pat. No. 5,554,719 and U.S. Pat. No. 5,565,544 disclose a processfor preparing a branched PHS directly from HPMC which comprises thesingle step of polymerizing a mixture of carboxylic acid and at leastone substituted phenyl carbinol such as HPMC.

However, it is highly desirable to have a linear DPHS and the prior artdoes not disclose this, much less a process for preparing the same.

Other prior art references which relate to the present invention includeU.S. Pat. No. 2,276,138; U.S. Pat. No. 3,547,858, U.S. Pat. No.4,544,704; U.S. Pat. No. 4,678,843; U.S. Pat. No. 4,689,371; U.S. Pat.No. 4,822,862; U.S. Pat. No. 4,857,601; U.S. Pat. No. 4,868,256; U.S.Pat. No. 4,877,843; U.S. Pat. No. 4,898,916; U.S. Pat. No. 4,912,173;U.S. Pat. No. 4,962,147; and U.S. Pat. No. 4,965,400.

All of the above-cited prior art and any other references mentionedherein are incorporated herein by reference in their entirety.

SUMMARY OF THE INVENTION

The present invention, in part, discloses a new derivatizedpoly(4-hydroxystyrene) (DPHS) of the structural formula set forth hereinand which DPHS is uniquely linear in character. Another aspect of thepresent invention is a process for preparing a derivatizedpoly(4-hydroxystyrene) (DPHS) having a novolak type structure whichcomprises the steps of (i) supplying a solution of methanol containingHPMC, (ii) subjecting said solution to an acid catalyzed displacementreaction for a sufficient period of time and under suitable conditionsof temperature and pressure to convert substantially all of said HPMC to4-hydroxyphenylmethylcarbinol methyl ether in said solution, and (iii)polymerizing said ether containing solution in the presence of asuitable acid catalyst for a sufficient period of time and undersuitable conditions of temperature and pressure to form a novolak typepolymer which is a unique and new DPHS polymeric material having amolecular weight of from about 1,000 to about 100,000, preferably fromabout 1,000 to about 50,000 and more preferably from about 1,000 toabout 10,000. One of the most important characteristics of the new DPHSis the fact that it is substantially linear (about 6% to about 40%weight percent) compared to the prior art PHS as determined by NMR, andhas a low polydispersity, i.e. less than about 2.0.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides, in part, a new derivatizedpoly(4-hydroxystyrene) (DPHS) having the following structure:

wherein n is from about 1 to about 10, and generally from about 2 toabout 6.

The present invention provides a novel DPHS and a novel process forpreparing PHS having a novolak type structure which comprises the stepsof (i) supplying a solution of methanol containing4-hydroxyphenylmethylcarbinol (HPMC), (ii) subjecting said solution toan acid catalyzed displacement reaction for a sufficient period of timeand under suitable conditions of temperature and pressure to convertsubstantially all of said carbinol to 4-hydroxyphenylmethylcarbinolmethyl ether in solution, and (iii) polymerizing said ether containingsolution in the presence of a suitable acid catalyst for a sufficientperiod of time and under suitable conditions of temperature and pressureto form a novolak type polymer consisting of DPHS.

More specifically, the present invention is directed, in part, to aunique, cost-efficient process for preparing a novolak type polymerwithout any of the prior art disadvantages and wherein thepolydispersity of the new material is surprisingly low, e.g. less than2.0 and generally about 1.5 to about 1.9.

It has unexpectedly been found that the use of a freshly suppliedcarbinol such as HPMC cannot be used directly to form the a DPHS havinga novolak type structure, and this is contrary to the disclosures setforth in U.S. Pat. No. 5,554,719 and U.S. Pat. No. 5,565,544. It hasbeen found that if a freshly supplied carbinol such as HPMC is nottreated as set forth in the present invention and before polymerization,the resultant polymer is a gummy mass which is poor in color and hard tofurther treat to arrive at the desired end product, i.e. the DPHSnovolak type polymer. Thus, it is essential and critical that HPMC beconverted to its ether form before the material is polymerized.

The carbinol such as HPMC is subject to an acid catalyzed displacementreaction in order to convert it to its methyl ether form. This step canbe carried out by use of an acid ion exchange resin such as Amberlyst-15(Rohm and Haas product) or M31 (Dow Product). The HPMC material issupplied in a methanol solvent wherein the HPMC is dissolved therein.The concentration of HPMC in solution is from about 1% to about 50% byweight, preferably from about 15% to about 30% by weight. Thisconversion takes place by merely contacting said HPMC containingmethanol solution with, e.g. the A-15 material either by running thesolution a fixed bed of A-15 or merely mixing the two materials togetherfor a sufficient period of time and under suitable conditions oftemperature and pressure. The temperature of the conversion step is notcritical and can be from about 0° C. to about 100° C. and the pressureis also not critical, but can be from about 0 psig to about 10 psig, oreven conducted under vacuum. The conversion time is also not criticaland is long as necessary to convert the HPMC to the methyl ether form.This time can be as long as several days at room temperature to as shortas 24 hours at 45° C. The critical factor in this conversion step is theconversion must convert substantially all of the HPMC to the methylether form before the polymerization step takes place. It is desirablethat the conversion be at least 90% complete, preferably at least 95%complete.

The second step is the polymerization step which is carried out with thesame methanol solvent which now contains dissolved therein the methylether form of HPMC. This polymerization step is conducted with the useof a suitable acid catalyst under suitable conditions of temperature andpressure to form the desired end novolak product.

The catalyst employed in the present invention process is critical andis selected from the group H₂SO₄, HCl, AlCl₃, H₃PO₄, oxalic acid, SnCl₂,BF₃, BBr₃, BCl₃, para-toluene sulfonic acid, and methane sulfonic acid.Thus, Lewis acids and protic acids having a pKa of less than about 4.75are suitable.

The catalyst is used in any amount in order to facilitate the reaction,i.e. polymerization, to yield the DPHS which has a novolak typestructure. Such amounts generally are from about one part per million(ppm) to about 100,000 ppm, or higher.

The temperature employed in the polymerization is generally less thanabout 120° C., more specifically from about 0° C. to about 120° C. Thereaction pressure may be subatmospheric, atmospheric, orsuperatmospheric.

The length of time which this polymerization step is conducted is notcritical and the only requirement is that the polymerization beconducted for a period of time sufficient to form PHS having a novolaktype structure. Generally, this period is at least five minutes and maybe as long as 25 hours.

After the polymerization of the reaction mixture (i.e. acidcatalyst+carbinol+any nucleating agent), the desired end product (DPHS)is recovered from the reaction product and the residual fractioncontaining any unreacted carbinol methyl ether can be recycled as partof the starting material for the next cycle. The end product (DPHS) maybe recovered from the reaction product by any method; for example, itcan be separated from the fraction containing the unreacted carbinolmethyl ether by, e.g. precipitation in water followed by filtration, orany other suitable technique. For example, an electronic grade of DPHScan be produced containing low ppb metals by removal of the acid with abasic ion exchange resin followed by removal of the metals by acid ionexchange resin. It is also within the scope of the present invention toutilize a nucleating agent like a seed monomer in order to prepare thereaction mixture. Such material does not have to be a carbinol nor doesit have to contain any hydroxy groups. Such nucleating agents mayinclude, without limitation, the substituted phenols and substitutedtriarylalkyls, and other polyphenolics such as THPE.

It is also within the scope of the present invention to employ a chainterminating agent after the polymerization step. Any type of chainterminating agent may be used as long as there is no substantial adverseeffect on the novolak structure of the DPHS formed.

It is also within the scope of the present invention that the DPHS maybe recovered by other methods in the art such as by spray drying.

In addition to the use of DPHS (with a novolak-type structure) in themicroelectronic chemicals market, such DPHS can be employed in standardnovolak applications such as varnishes, aniline printing inks, rawmaterials for epoxy resins, copying paper, tackifiers for rubber, andcrude oil separators and other applications as stated herein.

The following specific examples are supplied for the purpose of betterillustrating the invention. These examples are not intended, however, tolimit or restrict the scope of the invention in any way and should notbe construed as providing conditions, parameters, or values which mustbe utilized exclusively in order to practice the present invention.

Example 1 4-Hydroxyphenylmethylcarbinol Methyl Ether (HPME) Synthesis

To 15 gms of methanolic solution containing 22.2%4-hydroxyphenylmethylcarbinol (HPMC) was added 0.45 gms of AmberlystA-15 acid ion exchange resin. This mixture was allowed to stand for 72hours at room temperature. HPLC analysis indicates that the resultingsolution contains only 0.21% HPMC (99% conversion) with the remainderbeing HPME. This material thus produced is suitable for use as a rawmaterial in the preparation of the DPHS polymer.

Polymerization of 4-Hydroxyphenylmethylcarbinol Methyl Ether (HPME),Production of DPHS Polymer in Methanol Solution

To a 500 ml flask fitted with a nitrogen inlet, mixer, temperatureindicator and controller, and reflux condenser was added 226 gms ofmethanol solution containing 30.4% HPME (68.7 gms HPME) raw material.Using solvent distillation 131 gms of methanol was removed rendering asolution containing 72.3% HPME in methanol.

The resulting solution was cooled to room temperature. With stirring andunder nitrogen, 1.4 gms of aqueous 10% H₂SO₄ (catalyst) was added at 30°C. The mixture was heated over a 30 minute period to 35° C. and a secondequal portion of catalyst was added. This process was repeated threemore times at which time 7.0 gm of acid catalyst had been added with aresulting temperature of 50° C. over a two hour period. Thepolymerization mixture was then increased to 65° C., reflux temperature,at which time the mixture color was noted to be pink turning amberthereafter. Reflux was allowed to continue for

26 hours after which time the reaction mixture was cooled to 27° C.

The resulting reaction mixture was diluted with methanol to give asolids concentration of about 30% which was slowly fed intodemineralized water (1 part by weight methanol solution to 10 partsdemineralized water) to give a precipitated polymer product. Theprecipitated material was filtered and washed three times with 125 gmsof fresh demineralized water.

The wet-cake thus obtained was dried under vacuum at 40° C. until themoisture content was about 1% or less. This polymer was observed to havea GPC molecular weight of 4528 MW, a polydispersity of 1.6, and was oflight pink color.

Example 2 Comparative

In a similar polymerization run using a raw material containingsignificant quantities of HPMC in the presence of HPME, a polymericmaterial completely unsatisfactory for commercial purposes was obtained.This undesirable material was dark blue in color and tacky upon vacuumdrying. This material was also very difficult to filter and wash. Thiscomparative example is similar to those examples 1-11 set forth in U.S.Pat. No. 5,554,719 and U.S. Pat. No. 5,565,544.

It is to be understood that the remarks above contain some theory as tothe formation of DPHS with a novolak type structure; however, Applicantdoes not wish to be so limited.

Although the invention has been illustrated by certain of the precedingexamples, it is not to be construed as being limited thereby; butrather, the invention encompasses the generic area as hereinbeforedisclosed. Various modifications and embodiments can be made withoutdeparting from the spirit and scope thereof.

1. A epoxy or blocked isocyanate containing paint formulation which alsohas incorporated therein the composition of matter having the followingstructure:

wherein n is from about 1 to about
 10. 2. A highly viscous polymerhaving incorporated therein the composition of matter having thefollowing structure and which acts as a viscosity modifier therefore:

wherein n is from about 1 to about
 10. 3. A polymeric material havingincorporated therein the composition of matter having the followingstructure and which acts as an antioxidant therefor:

wherein n is from about 1 to about 10.